1. Field of the Invention
The present invention relates to semiconductors, more specifically it relates to etching Indium based III-V compound semiconductors.
2. Description of the Related Art
In the past chlorine based gases were used to etch indium phosphide (InP) using reactive ion etching (RIE). Unfortunately, this process produced indium chloride (InCl.sub.n n=1,2,3) as a by-product. The InCl.sub.n has a low vapor pressure and remained on the surface of the semiconductor. In an effort to remove the InCl.sub.n, the semiconductor was heated to above 150.degree. C., however, this procedure was unsatisfactory because such high temperatures damaged the semiconductor device being fabricated and limited the availability of suitable masks.
RIE of InP has been carried out using a mixture of methane (CH.sub.4) and hydrogen (H.sub.2) in which volatile organometallic group III compounds are formed. The etch rates that were achieved using this method were approximately 1000 .ANG./min. An etch rate of 1000 .ANG./min is too low to etch structures such as via holes of the order of 100 .mu.m.